1. Field of The Invention
This invention relates to improvements in self-cleaning filters. More particularly, this invention relates to filters for fluid media carrying fibrous or other forms of debris which tend to clog the filters.
2. Description of the Prior Art
Strainers and filters are employed to separate solids from fluids. Generally speaking, strainers are used to separate solids with an average width of 1/2 inch to 75 microns. Filters are used to separate solids with an average width less than 75 microns. In the case of strainers, the solids are collected on a screening media or strainer element and thereafter, the solids are removed from the screening media by backwashing. During backwashing, fluid is caused to flow in a reverse direction through the screening media and is collected by a backwash arm to clean the screen, as described, for example, in U.S. Pat. Nos. 4,818,402 and 5,152,891, which are hereby incorporated by reference. As used herein, the term "backwash arm" refers to a suction chamber or collection duct.
Filters typically collect solids in a disposable bag filter element or are provided with brushing or blow down systems to remove the collected solids. A shortcoming of bag filters is that they are expensive. In many cases the collected solids, such as hydrocarbon materials, must be placed in special containers and sent to landfills. Further, the brush and blow down type systems are inefficient and periodically require hand cleaning of the filter element resulting in expensive downtime and labor costs.
Accordingly, it is an object of this invention to provide a filter that is less expensive and more efficient to operate than the prior art filters.